Move WebInputMethodControllerImpl to core/exported/ & break dependencies.

third_party/WebKit/Source/web/WebFrameWidgetImpl.h

Index: third_party/WebKit/Source/web/WebFrameWidgetImpl.h
diff --git a/third_party/WebKit/Source/web/WebFrameWidgetImpl.h b/third_party/WebKit/Source/web/WebFrameWidgetImpl.h
index 74f07bef43ae0f34601438c30c01cfeec340bf7e..9dbf83ca161b1e8a39ecc158a3f3eb1eff000986 100644
--- a/third_party/WebKit/Source/web/WebFrameWidgetImpl.h
+++ b/third_party/WebKit/Source/web/WebFrameWidgetImpl.h
@@ -43,7 +43,6 @@
 #include "public/web/WebInputMethodController.h"
 #include "web/CompositorMutatorImpl.h"
 #include "web/PageWidgetDelegate.h"
-#include "web/WebInputMethodControllerImpl.h"
 #include "web/WebLocalFrameImpl.h"
 
 namespace blink {
@@ -119,8 +118,7 @@ class WebFrameWidgetImpl final
   void SetBaseBackgroundColorOverride(WebColor) override;
   void ClearBaseBackgroundColorOverride() override;
   void SetBaseBackgroundColor(WebColor) override;
-  WebInputMethodControllerImpl* GetActiveWebInputMethodController()
-      const override;
+  WebInputMethodController* GetActiveWebInputMethodController() const override;
 
   Frame* FocusedCoreFrame() const;